Continuous tunnel-kiln.



G. H. BNAMN commons TUNNEL mw. APPUCUON FlLEU FEB. l. 'iYf RENWU) IULY I6, IBIS.

lutentm Mm'. 121m.

3 sHEHA-SHEE 'EN G2.

lil

UNITED STATES PATENT OFFICE.

GEORGE BILLARD BENJAMIN, F NEW YORK, N. Y.

CONTINUOUS TUNNEL-KIQN.

Application led February 1. 1817, Serial No. 145,959. Renewed July 16, 1918.

.To all' willem if 'may #02u-wn.'

Be it known that GEORGE llrnLAnn JAMIN. a ritizen of tho United Staten. residing :it` New York, in the county' and Stute oli New York, have invented rel-tuin new Yand ueeful Iniprm'emente in (lont inuoue Tunnel- Kilns, nl" which the following is n epemifiean tion.

My invention relates to certain improve ments in continuous tunnel kilns of the inulllv iype. sru'h :le are eel'ierinlly adapted for use in tinA mnnufm'turr 0l` tiles. pottery. and the like. f

in :i prior n'iplicntion. Serial iifetl ,llziy El. 'lrlllh l have desc lied u ron- .elruriion in, wlxirl the` limiting ineens e1nploj'ell consiste of :i Series of Separate ellenihers nrrnnged longitudinally in line... on ozu-l1 eide of the main clmmhel, und @urli of suoli rlneauhers` :nlnpted to yhe fed with gne find nir under pressure. proportioned to produce complete Qomlluetion at the4 burner orifices, thrprmluf'fi of combustion living drawn friuli ruoli ohzlnihor and illilizeil to heut. lln` :lir need in vombumion with the gue in ih@ hunting; rlminhere. or 'intrmluced into the niflin rlmmhor. In muli application here l'mihrr l eril ied n menne wherelrxy limiti-l :lil intrmlzufml inlo the mitin eli-umher in whirh the gonfle under rezztment :ire paused. le poeitirely circulated through such goodie.

hir premi-it invention ronnie@ in u molliiirntioi.- n2' the ron;-liiivl io| dwrrilwii in Sui-i1 prior upplirnlion. eo [2n-:1s reluiee to the mn- Slrurtion und plurime of the heutiug rhum-- hows, ee :Ilm the urnsngvmou of the pussullr. h ri-l'leon nl which thij :xincirculutril over und around the good.l rurrird through the niuin chandler. ie more prrfevtly heated; also to olher rumlilienlion. which will he. poinlefl oui in thel `periii:'.itio|:.

I wish it uni'loletood that my impl-lived rontinuouf; kiln is noi only adapted for use in thil umnufm'tlrre of tiles. pottery :md the like, hut also in the umnulnrtuw ol brink ain-"l For annealing und other treatment of metals, ehr.

'lhi- :n 'conipnnyiug drawings will serve to illusllzur un invention. in ulliifh Figure l ie .-i longituflisml willen. 'Fim L an :i verticali i su: liz-o line le-"ll fi Fing. l. 191g. 3%

sorlion on the line Figi. vll5 ri million Corre o anni allowing w modifica- Specication of Letters Patent.

YThe grner-:1l zn'rungfemont of the gas und air Patented Mar. 4, 1919.

Serial No. 245,218.

tion. Fig. 5 is a section corresponding to Fig. 3 and showing a further modification.

Referring to the drawings, 5 indicates theJ mein chfunber, which may be of any Suitable construction. As the kiln is a long piece of `.ppardtus, onlyrsuficient length is illustrated in Figs. l and 2 to show its general Conetruction. Situated within the kiln, on each Side, and arranged longitudinally inline, are individual heating chambers 6, 6a, 6l. 6, etc. These heating chambers may be formed of baked clay 01' built up of brick. and nre located at a. distance from the bide walls and top of the main chamber, so to form :tir passages 7 between the. chambers and the walls. The chambers 6 are so elesigned that their Side walls 8, und the inner wallsl 9 of the main chamber, will occupy parallel vertical planos. The top wall 10 of the` heating` chinnbere (i, is inclined and locuted in a plane parallel to the, plane of the roof l1 of the 11min chamber. The portion of the nir passage 7, between the top wnll 10 of the heating;F chambers 6 and the roof 11 of the main chamber. is inclined in an upward direction. The object of this construction is lo throw the incoming nir against the roof 11 of the main chamber. from which it is deflected in u downward direction through the goods 12. under treatment in the 11min rhznnher. The interior 13 of the chambers is given sui-h size as to permit free comlmetion of the me und nir introdueed .into the bottom ol the chambers through the burnerl il. The burners 14 are (zonnet-ted llirongrh thv mixing pipe 15 to :L gas supply pipe 153 and nn nir supply pipe 17. The gas transmitted from pipe 16 is under pressure from pump 1R. und the nir from pump 19.

pumps und burners is full),r described in my prior npplintion, to which reference hns horeinhefore been mede. and also in my prior Patent No. 948.5% dated Feb. 8, 19,10.

'Tinl purpose m giving to the heating 100 ('linnihvre the interior size. and placing them as dmvribed. is two-fold: First, to permit instantaneous combustion of the gas und air introfliufed into the chambers at the burner e'iiiees and tlnlrefore, the immediate de- 105 velopinmu of all'of the heat. units carried hy the ooinhustihle mixture` with the result tha perfect combustion is obtained with vri-y mum higher temperatures than ie otherwise possible using gas and air; and

2 Lasagna second, to utilize the heat radiated from the two sides and top of the heating chambers for heating the air which` is circulated over the goods under treatment in the kiln, there- 6 by using the radiated heat units to the best advantage.

In view of the fact that kilns such as-described in this specification, may be employedy for treating goods containing more 10 or less Iwater, and the further fact that when water in' the form of steam is mingled with heated airithe specific gravity of the mixture is less\than of air alone, it is necessary,

in order -to cause the air or mixture to circolate through' the goods under treatment in the kiln, to provide means for creating a positive circulation of said air" or mixture,'

and this is accomplished by means of a pump 20, which is connected to the interior of the kiln at its induction orifice, through an air passage 21, and at its eduetion orifice throughran air pipe 22, which is in communication with the passage 7 between each heating chamber and the inner walls of the' kiln (see Fig. 4). It is sometimes desirable to allow fresh air to enter thepassage 7, and to permit this I provide the valves 23 in pipe 22. I also provide a valve 24.in the pipe 25 from the eduction orifice of the pump 20, which when opened, and the valves 23' closed, allow the air to be drawn out of the kiln.

It-is also sometimes desirable to add to the'heat of the air introduced into the pas-l sage 7, or in other words, impart heat *units in excess of those added by radiation from the chambers 6. To accomplish this, the air pipe 22 is carried through a flue 26, which conveys the products of combustion from 0, the chambers 6 to the chimney stack 27 (see Fig. 5). In this figure, the air enters the pipe 22 through an opening 28 in pipe 22. It desired, the pipe 22 may be connected to the eduction orifice of the pump 20, in which case circulation of the air will be etected,

as in the manner shown in Fig. 4, and further, heat units added to the air by the heat units passing through the flue 26. 1

The goods 12 under treatment. are mounted on a truck 29, which moves over rails 30 situated beneath the main chamber. In order to compel the hot air to pass through the goods on the truck 29. rather than How along the outer walls of the Achambers the p of the truck is provided with a plato 31, the sides 32 of which are turned downward at a right angle, and when the truck is. progressed, move in boxes 33 which are filled with sand, thus forming a sand seal. An opening 34 is provided in the plate 31.

l wish it understood that the drawings; in this application are in n sense diagrammatic, and merely intended to illustr-.ite sur-.h n construction as may be used. nml that very 66 many modifications may be made, not only in the general construction, but in the size and relation of pipes and passages, position of the valves, etc., without in any wise `departing from the intent of my invention.

The general operation of my improved kiln will be readily understood. Assuming the goods to be treated in the kiln` to contain some moisture, and that it. is desirable to evaporate such moisture before subjecting the goods to the temperature necessary to vitrify the material, the gas and air introduced into the chambers 6 is regulated S0 that the temperature in this chamber will be comparatively low.; more gas and air will be introduced into chamber 6, more into 6* and still more into chamber 6, it being assumed that the maximum temperature of the kiln is at 6. For the purpose of description it is assumed that the drawing (Fig. l) shows one half of the length of the kiln. It may be further assumed thatY vitrificaton is effected in thevzone in which'the chambers 6 are located. Consequently all that is necessary to temper the goods is to decrease the heat from such Zone Gcto the outlet of the kiln, in which case it is not necessary to introduce any gas into the chambers beyond 6c. `Sometimes, however, it is necessary to hold* the vitrifying temperature for a time, in which case the gas may be introduced into one or more of the chambers beyond 6 in any proportion required to give the necessary heat. l

It will be understood that by reason of the arrangement of the chambers disclosed, and the fact that each chamber is independent of the t other chambers, both structurally and so far as its supply of gas and air is concerned, the temperature at any portion of the length of the kiln can be regulated to suit the rcquiremeuts of the goods under treatment. It will be further observed that the construction is such that the air carrying the' ,heat units and acting on the goods under treatnlent` can be regulated to suit requirements. For instance, assuming the goods under treatment to contain more or less moisture when introduced into the kiln, it is an advantage not to cause the nir to pass over the goods more than once, in which caso the air will be fed through the pipe 22 nud drawn out through the pump 20 to he discharged into the atmosphere, thus getting rid of themoist nir. liy reason of the ronstruction disclosed. the air fed to the furnnco over the heating chambers l, muy be drawn out to he discharged into the almosphere, wherens tln` nir fed to the t'urmu-e over the heatingr chambers il, 6* and li may be continuously circulated, thus converting the hout units nud progressively adding to them, und furtluxurold or heated nir muy bc fed into the kiln nt that portion of the kiln beyond the chamber li.

The requirements of temperature in a tunnel kiln in which the `goods treated are moved continuously or by step-bystep motion through the kiln, are so various, owing to the difference in size, character or material of which the goods are made, that no general statement can be made regarding the temperatures to be produced at any point or points alon the length of the kiln. Such temperatures, however, can readily be determined by experiment, and one articular advantage of the kiln* describe in this specification is that by regulatin `vthe temperature of gas and air introduce iito the heating chambers, alone or in connection with'the air introduced into the main chamber, hea-,ted or cold, a greater number of technical results can be obtained than is possible inany other furnace construction of which I am aware. 1

I have shown in the drawings but one pump for controlling the circulation of the air. Where the air is to be controlled in differing manner over different sections, the

number of pumps employed will be in accordance with the variations in the air cir culation. Practically, however, the valves and other devicesniay be used in connection with a singleV pninp. Such arran ment is so well known, that is has not een considered necessary to illustrate the employment ofzl'riore than one pump.

Haying thus described m invention and themanner in which it is to fused, I claim: f1. A tunnel oven of the type described, comprising a main chamber, a plurality of structural y inde endent .heating chambers arranged longitu nally in line on .each side of the main chamber, each heating chamber having a vertical height correspondin to the maximum horiontal plane occupie by the goods under treatment in ff fg] throughthe chamber, and such c a, located at such a distance from the""`sid walls and top of the main chamber as to provide an air passage between the res ective chambers, and said heating cham ers having such an interior capacity as to permit free combustion V01E the gaseous fuel introduced ainto Vthe bottom of the chamber, t0-

.getherr with means for introducing gas and air under pressure into said heating chamers.

2. A tunnel oven of the `type described, comprising a main chamber, a plurality of structurally independent heating chambers arranged longitudinally in line on each side of the main chamber, each heating chamber having a vertical height corresponding to 'the maximumhorizontal plane occupied by the goods under treatment in passing through the chamber, and such chamber located at such a distance from the side walls and top of the main chamber as to provide an air passage between the respective chambers, the said heating chambers having such o .the .main c amber, each 'heating chamber 1 *cated at-a distance from the top and side walls of the main chamber, said chamber consisting o'f ltw'oparallel vertical walls and an `i`iiclined topwall .and having a vertical height corresponding ftoj the maximum horizontal plane occupied by the goods under treatmentin passln through the chamber, and such` chamber iaving such Aaninterior capacity as to permit free combustion of the gaseous fuel introduced into the bottom of the chambentogether with means for introducing and air under pressure into said heating chamber.

`i. A tunnel oven of thc type described, comprisin a main chamber, a plurality of structurallgy inde iendent beating chambers arranged longitu inally in line on each side of the main chamber, each heating chamber having a vertical height corresponding to the maximum horizontal plane occu t ied by the goods under treatment in easing t irough the chamber, and such chainllier located at a distance from the side walls and. top of the main chamber, said heating chamber having such an interior capacity as'to permit. free combustion of the gaseous fuel introduced into the bottom ofthe chamber, means for treatment in the main chamber and out o? the main. chamber.

5. A tunnel oven of the type described, eomprisin a main chamber, a pluralitv of structurally independent heating chambers arranged lon itudinally in line r'on each side of the main `c amber, each heatin chamber having a vertical hei ht correspon ing tQthe maximum hmfizohtalg plane occupied by the goods under treatment in passing through the chamber, and such chamber located at a. distance from the side walls and top of the main chamber, said heating chamber having such an interior capacity as to permit free combustion of the gaseous fuel introduced into the bottom of the chamber, means for introducing heated air into the main cham lier between the sides of thofmain chamber and the inner sides of the heating chambers, and means for causing the air introduced to flow over the heating chambers and in u. downward direction through the goods under a. main chamber, a plurality o1"aend'ent heating chambers' treatment in the main chamber and out of the mainv chamber.

6. In a Atunnel oven of the type described, the combination of a main chamber, a series of inde' endent heating chambers arranged longitulinally in line on each side of the main chamber, each of said heating chambers situatedvat a distance fromthe `side walls and top 'of said main chamber so that an air passage shall exist between the two; said ieating chambers hav-ing a vertical height corresponding to the maximum horizontal plane occupied by the goods under'` treatment in fpassing through the main chamber; means or introducing aseous fuel separately into each of said eating chambers; means for controllin the temperature of each of said heating c ambers, together with means for creating an air circulation in an upward direction over said heating chambers and then in a downward direction over said heating chambers and through the goods under treatment in the main chamber.

47. A tunneli oven of the type described, comprising a main chamber, a series of independent, heating chambers arranged longitudinally in line on each side of the main chamber, each of said heating chambers situated at a distance from the side walls and top of said main chamber so that an air passage shall exist "between the two; said heating chambers having a vertical height corresponding to the maximum horizontal plane occupied by the goods under treatment in passing through the main chamber means for introducing gaseous fuel separately into e-ach of Said heating chamu bers, means for controlling the temperature of each of said heating c ambers, together with means for introducing air in an upward direction in the space between the back of the heatin chamber and the side Walls of the main c amber, and then causing the air after passing the heating chambers to pass in a downward direction through the goods under treatment in the main chamber.

8. In a tunnel oven of the type described, the `combination of a main chamber, a series of inde endent heating chambers arranged longitudinally in line` on each side of the main chamber, each of said heating chambers having their tops substantially in the same horizontal plane as that occupied by the goods under treatment in passlngi through the chamber, an air passage between said chambers and the walls of the to of the main chamber, means for heating said heating chambers, together with means -for creating an air circulation in an upward direction through such passage over the rear of said heating chambers and then in a downward direction over said heating chambers and through the goods under treatment in the main chamber.

In testimony whereof I aiiix my ture, in the presence of two witnesses.

GEORGE .HILLAR-l) BIINJAMIN.

signa- Witnesses:

HELEN E. Koersen; Lns'rnn BEARnsLnY, 

